I just stumbled upon this really great map of Paris and the Metro (click on link)I had some fun hunting down Harry's New York Bar (Paris) at 5, Rue Daunou, between the Avenue de l'Opéra and the Rue de la Paix. I recall that the beer there was great when I last went there, some years back.

The website http://www.acme.com where I found the map is worth a look as well. Lots of interesting software (maybe mostly Linux-related, I think).